Door lifting apparatus for grain pits and the like



Aug- 21, 1 R. A. CHRISTISON DOOR LIFTING APPARATUS FOR GRAIN PITS ANDTHE LIKE F'i'ld July 26, 1947 RICHARD/4. CHR/5 r/so/v- INVENTOR.

Patented Aug. 21, 195i OFFICE DOOR LIFTING APPARATUS FOR GRAIN PITS' ANDTHE LIKE Richard A. Christison, Decatur, Ill.

Application July 26, 1947, Serial No. 763,960

1 Claim.

My invention relates generally to improvements in apparatus by whichrelatively heavy trap doors may be lifted in a manner requiring aminimum of manual effort by the operator, and is particularly adapted tothe lifting of such doors as are usually provided in the runway orplatform covering the receiving pit of grain elevators.

It is well known that the usual trap door forming a portion of theplatform over a grain receiving pit is necessarily'of'heavyconstruction, because the grain laden vehicles are driven over it toreach a position suitable for unloading grain into the pit. And it isalso well known that as a result of the necessity for manually openingand closing doors of the usual type'of receiving pit, severe operatorfatigue is inevitable, which tends to slow down the unloading routineand requires added man power and subsequent increased operating expense.

Various methods of overcoming the aforesaid difficulties have been used,most of them compris ing the arbitrary installation of costly motorequipment or else improvised and unstaple apparatus not conducive toreliable and uninterrupted operation under heavy and constant service.In elevator operation I have found that the difficulties and defects inservice incurred as a result of these last mentioned door lifting meansmay lead to serious confusion as well as expense due to work stoppagefor repairs and adjustanents.

My improved door opening apparatus contrives to overcome all of theaforesaid difficulties and disadvantages by the embodiment ofeconomical, simple, and durable construction, high efficiency in use andsuch structural features as will insure its safe and convenientinstallation and operation, all of which is comprised in one of the moreimportant objects of the present invention.

Another important object of the invention is to provide a door openingapparatus which is constructed and arranged to be fixedly thoughpivotally mounted on an inner side wall of a receiving pit, and adaptedfor yieldable connection to the trap door of a grain receiving pit forresiliently raising and opening said door and so as to be yieldable whenacted upon by the force aping is accomplished by means of a novelstructure comprising the invention which is disclosed in the followingdescription, together with the accompanying drawings referring to thepreferred form of the invention and in which:

Fig. 1 is a top plan view showing the trap door in open position, andone corner of the platform broken away to indicate more clearly thespring member and the point of its attachment to one end wall of thepit.

Fig. 2 is a sectional view taken on the line 22 of Fig. l, but showingthe door in closed position and the arrows showing the course of thedoor when swinging open to the position indicated by the dotted lines atT, while the dotted lines at U indicate the position of the liftingapparatus when the door is swung to the position shown at T.

Fig. 3 is an enlarged perspective detail of the main pivotal plateassembly shown at V in Fig. 2.

Fig. 4 is an enlarged perspective detail of the pivotal clamp assemblyshown at W in Fig. 2.

Fig. 5 is an enlarged detail perspective view of the cradle clampassembly shown at X in Fig. 2.

For the purpose of this disclosure the invention is described herein asapplied to a grain elevator pit, but it is to be distinctly understoodthat it is not my desire or intent that the invention be limited to thisparticular embodiment and illustrative use, and that modifications andchanges in details of structure and arrangement of parts residing withinthe scope of the appended claim may be made without departing from thespirit thereof.

Referring'to the drawings in detail, a spring actuated, pivotallyoperable frame member IQ is shown that comprises a circularly curvedloop portion ll extending forwardly so that its opposing ends convergeto a pointed form as at A in Fig. 2 terminating thence in and as a levermember [2 for the purpose of slidably contacting the inner face of thetrap door 45 in the act of raising the same, as shown particularly inFig. 2.

The pivotal plate members [3 and l3a are provided to clamp and holdfirmly the frame member It], thus comprising the means enabling thepivotal and subsequent door-lifting action of said frame member l0 as awhole, see Figs. 2 and 3.

The plate members [3 and [3a are held in se-. curely clamped position asshown particularly in Fig. 3 by means of the screws I l protrudingthrough said plate member I3 to threadably engage said plate member l3a,and it is obvious that the king bolt l5 pivotally engages both the 3plates 13 and [3a. It is obvious, too, that the king bolt i5 is adaptedto threadably engage at its threaded end a nut l6 and lock nut l1, andthat the shank l5a of the bolt is adapted for through engagement withone side of the grain pit as shown at Yin Fig. 1.

- In actual use and to effect the pivotal and door opening action of theframe member I!) as just mentioned, the hereinafter described functionand action of the other associated parts of the present invention willbe observed. A pivotal clamp assembly is provided and adapted forclamped engagement with the loop portion I l of said frame member Iii(see Figs. 2 and 4), comprising the clamp is held in fixed position onsaid loop portion i i by the bolt [9 arranged for through engagementtherewith, and the nut threadably engaging said bolt [9. The outer endsof said clamp i2 being adapted to receive in through engagementtherewith the bolt,2l threadably engaging the nut 22. Said bolt 21 isprovided for the purpose of engaging the loop 24 at the rearward end ofthe curved arm member 23 which is formed to follow the shape of saidloop portion ll and which rests in the cradle clamp 26 held in fixedposition on said loop portion II by the bolt 2? arranged for throughengagement therewith, and the nut 23 threadably engaging said bolt 2'1.The outwardly flaring ends 26a of the clamp 28 are adapted to receivethe outer swingable portion of the arm member 23 adapted to resttherebetween and against the bolt 27 as shown in Figs. 2 and 5. The loopat the forward end of the arm member 23 engages the rearward end of therelatively long spring 29 which engages at its forward endthe eye-boltheld in through engagement with the end "53 of the receiving pit wall bythreaded engagement with the nut 35. t ,7 g

It will appear obvious that the arm member 23 in its particular positionshown on the loop portion H serves to maintain the pulling spring actionrequired to produce the lifting action of the frame member iii. Forexample, were the rearward end of the spring 29 to be attached wheretheclamp 28 is now shownand the arm member 23 omitted then the frame memberI0 would be deprived of a good portion of its lifting power by the timesaid frame member H) was pivoted on the bolt i5 to the position shown atU in Fig. 2. H t r r V In the arrangement shown in Fig. 2, it will bereadily evident that when the frame member I0 actually is in theposition as indicated by U, the pull by the spring 29 is still exertedfrom a point adjacent the then bottom portion of the frame member l8 bymeans of the pivotal and subsequent unfolding action of the arm member23 as 4 to the position indicated by the dotted lines at W in Fig. 2.

While the dotted lines shown at Z in Fig. 2 indicate a stop member tohold the door against falling backward when it is open, it is pointedout that any suitable stop means may be provided for the purpose, and noclaim is made to this particular feature.

The grain receivingpin in the present disclosure having the side walls40 and 4 I, end walls 12 and 43, platform 44 and trap door 45 as well asthe concrete foundation 46 are shown merely as one example of many wellknown types of grain receiving pits in which this invention may beinstalled and used, said pit and foundation not comprising any part onwhich claim is based.

It is obvious that any suitable latch means may be provided on the cover45 for the purpose of latching it to theplatform 4-4 of the pit and suchlatch means is deemed unnecessary to be shown.

mam:

A trap door opene'r for a trap door having a horizontal hing at one endand a door frame mounted thereunder, said trap door opener comprising aframe formed with an arcuate inter-- mediate portion and convergent endportions, one of said end portions extending beyond the con-- vergingpoint forward to form a lifting memberfor sliding and shifting contactwith a trap door,

a swivel support for said frame mounted on the normal upper end portionthereof and adapted. to be mounted on a door frame, a curved arm.

member swingably mounted on the arcuate portion of said frame, a springsecured at one end to th distal end of said curved arm, an eyeboltsecured to the other end of said spring and.

adapted to be secured to a door frame, a cradle member fastened to saidframe between themounting, of saidcur-ved arm member thereon andthedistal end of the normal lower end portion thereof, said curved armmember arranged so that the end to whichthe spring is secured rests insaid cradle member when said frame is in position as when the door isclosed.

Name Date 474,268 ..Sidenstricker May 3, 1892 762,741 Moos June 14, 19041,073,003 vTroyer Sept. 9, 1913 2,327,026 Deuring Aug. 17, 1943

